[Stoves] Cuber and size of densifying machines. (no longer Re: The wood and char and fuel "debate" )

[Tom Miles]

Richard,

 

You probably mean 0.6 g/cm3 (37 lb/ft3) which is very good that’s better than most commercial wood pellets. For reference the dry density of sawdust is often about .160 g/cm3 (or 10 lb/ft3). The loose density of straw is about 0.08 g/cm3 or (5 lb/ft3). The press roll on a pellet mill exerts about 142 bars (2000 psig). If you can get those densities by selecting materials, wetting, pressing at 12 bar and drying you are doing very well. 


Tom

 

From: Stoves [mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of Legacy Found
Sent: Thursday, March 06, 2014 10:46 AM
To: Discussion of biomass cooking stoves
Subject: Re: [Stoves] Cuber and size of densifying machines. (no longer Re: The wood and char and fuel "debate" )

 

Crispin, what densities are you seeking. We have seen densities of up to  0.6kg/cm^3 by use of really fine granular material charcoal sawdust and certain other ag residues as infiller in hand presses generating only about 12 bars pressure.

I have not attempted pellet production but have no doubt that high pressure is not needed: Rather its more about attention  to blend particle density and size and variations between these (sorting coefficients) that makes the difference density wise. 

May look into it if anybody is interested in the fuel pellet world.

Richard

Sent from my iPhone


On Mar 6, 2014, at 11:38, Crispin Pembert-Pigott <crispinpigott at outlook.com> wrote:

Dear Friends

 

I agree with Dean on this score. The air flow through the pellets strongly affects the way they burn if the device is constructed such that the fuel contributes a significant element of air control.

 

These devices

<image002.jpg>

 

Are ‘cubers’ in that they are producing densified lumps that can be put into a stove. But they will work best in a large stove such as is used in China for space heating and cooking.  The input material is straw and other stover.

 

The mechanism is an eccentric roller running inside a perforated cage at maybe 60-100 RPM. As Tom notes, power consumption is about 110 kW.

 

So far I don’t think the product is economically viable as there is a subsidy involved. What we need is a breakthrough technology that will make densified fuel without the need for heat.

 

Regards

Crispin

 

 

 

Hi Paul,

 

I have seen the very small pellets sold for heating stoves in the US burn very cleanly. Larger sized pellets did not burn as cleanly. 

 

Best,

 

Dean

_______________________________________________
Stoves mailing list

to Send a Message to the list, use the email address
stoves at lists.bioenergylists.org

to UNSUBSCRIBE or Change your List Settings use the web page
http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org

for more Biomass Cooking Stoves,  News and Information see our web site:
http://stoves.bioenergylists.org/

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/stoves_lists.bioenergylists.org/attachments/20140306/25cdb3ee/attachment.html>